Synchronism-indicating means



Oct. 23, 1928. 1,688,790

. E. D. cooK SYNCHRONISM INDICATING MEANS Filed June 6, 1927 Inventor: Ellsworth D.Cook,

l-iLs Attorney.

Patented a. 23,1928.

UNITED STATES 1,688,790 PATENT OFFICE.

ELIJSWOBTE "D. COOK, OF SCOTLIA, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

sYNcnnomsm-mmcmmc mus Application filed June 6, 1927. Serial No. 196,800.

My invention relates to means for indicatin synchronism between voltages on a plurality of conductors such as those comprising parts of the usual power distribut on system and it has for its purpose to provide means 'whiclT* may be economically constructed and which will furnish the desired indication in a reliable and satisfactory manner.

A principal object of my invention is to provide means of the type indicated WlllCl'l dispenses with the use of potential transformers of the usual type and in which the indication may be had by utilizing a synchronoscope of a standard commerclal construction, such for example as that shown in Patent No. 1,641,693 to David R. Price and Francis H. Bowman, synchronoscopes, issued September 6, 1927, and which is assigned to the same assignee as the present application.

A further purpose of my invent on 1s to provide means of the type indicated 1n which the synchronoscope may be situated at any convenient distance from the conductors the voltage of which is to be synchromzedand in which its operation will be substantlally unaliected by extraneous fields and disturbances. 1

The novel features of my invention Wlll be set forth with partioularitydn the appended claims. My invention itself, however, both as to its organization and method of operation together with further ob ects and advantages thereof may best be understood by reference to the followlng description taken in connection with the accompanying drawing in which the single figure represents a preferred embodiment of my invention. i

Referring to the drawing, 1 and 2 represent conductors upon which are lmpressed voltagesthe synchronism of which 1s to-be indicated. These conductors are represented as passing through high tension bushings or insulators 3 and 4respect1vely, which beof the usual oil filled or condenser type such as those which are employed with the usual transformer or oil switch case. 5 represents a synchronoscope of the type set forth in the above mentloned patent and which Iemploy in connection with my invention.

Within the bushings 3 and 4 and represented by dotted lines in the drawing are .ing

concentric cylindrical conducting sheaths 6 and 7, and 8 and 9 respectively. The outer sheaths 7 and 9 are located near the inner surface of this bushing and are maintained at ground potential. The inner sheaths are dielectrically separated from the conductors 1 and 2 and from the outer sheaths and have voltages impressed thereon which are dependent in magnitude on the distance of the sheaths from the conductors. These sheaths constitute a capacitance transformer the construction of which has been set forth with particularity in Patent No. 1,657,249 to Eugene D. Eby issued January 24, 1928. The sheaths 7 and 9 are connected together through a conductor 10 and through conductors 11, 12 and 13 to ground potential. The inner sheaths 6 and 8 are connected through conductors 14- and 15 respectively to the grids of'the electron discharge devices 17 and 18. The electron discharge devices 17 and 18 and also the electron discharge devices 19 and 20, the purpose of which W111 be set forth, are of the usual three element type and have their cathodes energized through circuits 21 and 22, which are respectively connected to the secondary windings of cathode transformers 23 and 2 1 respectively. The primary windings of these transformers are energized from a source of alternating current which is represented in the drawing as an alternating current generator 25' which is, in turn, driven by a direct current motor 26 from a source of ener 27.

For the purpose of supplying gri bias voltage and anode voltage for the various electron discharge devices employed energy sources 28, 29 and 30 are provided, these being represented in the drawing as'direct current generators mounted upon the shaft of the generator 25. The armatureof the generator 28 is connected. to a circuit includconductor 31, resistance 32 and conductors 12,13 and 33. Thus the right-hand end of the resistance 32 is at ground potential and the left-hand end is at a potential below ground by an amount dependent upon the source 28. This potential may be varied as desired by means of the resistance 63 connected in series with the field coil of the generator 28. The grids of the electron discharge devices 17 and 18 are connected through resistances 34 and 35 respectively and conductor 36 to an adjustable point upon the resistance 32 thereby providing a suitable negative potential for the grids of hese devices. The anode circuits of the de ices 17 and 18 are supplied with voltage from the generator 29 through a circuit including conductor 40, primary windings of the transformers 41 and 42, conductors 43 and 44, space between the anode and cathodes of the devices 17 and 18 to the cathodes of these devices and thence through circuit 21 and conductors 11, 12, 13 and 33 to the opposite side of the source of potential 29. Likewise the anodes of the devices 19 and 20 are supplied with voltage from the sources 29 and 30, througha circuit including these sources connected in series, conductors 45, reactors 46 and 47 respectively, spaces between the anodes and cathodes of the devices 19 and 20, to the cathodes of these devices and thence through circuit 22, conductors 11, 12, 13 and 33 to the negative side of the source 29. The grids of the devices 19 and 20 are supplied with biasing voltage through conductors 48 and 49, secondary windings of the transformers 41 and 42 respectively and condoctor 50 which is connected to a suitable point on the resistance 32. The output cir-- cuit of the electron discharge device 19 is connected through a blocking condenser 50 and conductor 52 to two branch circuits, one including a resistance 53 and one of the coils of the synchronoscope 5 to round at the point 54, and the other includmg the inductance 55 and a second coil of the synchronoscope 5 to the point 54. The output circuit of the electron discharge device 20 is connected through a blocking condenser 56, conductor 57, resistance 58 and a separate c011 of the synchronoscope 5 to ground at the point 59. The description and operation of the synchronoscope 5 is. fully set forth in the above mentioned patent to David R. Price and Francis H. Bowman and, therefore, will not be more fully explained here.

When voltages are impressed upon the conductors 1 and 2, a portion of these volta es will ap ear between the conducting sheat s 6 and 7 and 8 and 9, these constituting in eifect capacitive connections with the conductors 1 and 2. This voltage is impressed upon the grids of the electron discharge devices 17 and 18 respectively through the conductors 14 and 1.5 and resistances 60 and 61 respectively. The imped-- ance of the input circuit including devices 17 and 18 is very high such that no appreciable current flows through the conductors 14 and 15 and as a result the voltages upon the grids of the devices 17 and 18 bears a substantially constant relation both in phase and magnitude to the voltages on the conductors 1 and 2. Thisis a articularl important feature due to the, act that i current is allowed to flow in thesecircuits the phase relationbetween the voltage on the grids of the devices 17 and 18 and that on formers constituted by the sheaths 6 and 7 and 8 and 9 are peculiarly adapted to the resent purpose. The current which can e drawn from these devices is very small notwithstanding that the impedance of the circuit connected thereto may be relatively low. B making the circuits including the grids 0 the devices 17 and 18 of high im-' pedance this current can be maintained at such small value that the voltages on the grids of devices 17 and 18 will bear a substantially constant phase relation to the voltage of the conductors 1 and 2 respectively.

The amplified voltages which appear 1n the anode circuit of thedevices 17 and 18 are impressed upon the grids of the amplifiers 19 and 20 through the transformers 41 and 42. The devices 19 and 20 operate as power amplifiers for supplying currents to the synchronoscope 5.

In the design of the apparatus the circuits are so arranged as to minimize the shift in phase of the voltages between the capacitance transformers and the synchronoscope. Such inductance and capacitance units as are necessary are so arranged in the circuits and are, of such magnitude that their effects on the phase relations mentioned are minimized. The cathode circuits of the tubes are maintained at ground potential as are also the sheaths 7 and 9 of the capaci tance transformers. The tubes 17 and 18 are located in comparatively close proximity, as for example, within a range of fifty feet, or so, to the capacitance transformers. The remaining a paratus may be located at pleasure. By liliese means distributed capacity efiects are minimized and the apparatus is protected against the efiects of extraneous fields and influences. For this reason it will be noted that the external sheaths 7 and 9 are somewhat longer than the sheaths 6 and 8 thereby protectin the latter from outside disturbances. Wit the apparatus as thus constructed the volta es appearing in the out ut circuit of the evices 19 and 20 will ear the same definite phase relation to the voltage of the conductors 1 and 2 as that which appears between the sheaths 6 and 7, and 8 and 9 and the operation ofthe device 5 will be as definite as though directly connected to conductors 1 and 2 through potential transformers of the usual type.

The operation of the device 5 is such that if the frequency of the voltage appearing in the system, of which the conductor 1 is a part is greater than that in the system 2 then the pointer 62 of the device 5 will HID - phase,

gradually move to the right whereas if the frequency of the system 1. is slightly less than that of system 2 then the pointer 62 will gradually move to the left. If the systems 1 and 2 are in synchronism and. in the grids of the discharge devices 17 and 18 will be simultaneously positive and negative and likewise the grids of the de vices 19 and 20, with the result that the current flowing from the anode of the device 19 through the condenser. 50 will be in phase with the voltage of the conductor 2 and likewise the current flowing from the anode of the device 20 through the condenser 56 will be in phase with that in conductor 1, and therefore the. ointer 62 0f the indicating device will stand at a point on the scale, as at the center, indicating that the systems 1 and 2 are in synchronism and in phase. If the system 1 is in synchronism with the system 2 but in phase opposition then the grid of the device 17 will be positive when the grid of the device 18 is negative, this effect being reflected in the output circuit of these devices'and on the grids of the devices 19 and 20 with the result that'current flowing in the output circuit of the devices 19 and 20 will likewise be in phase opposition. The needle will then fail to assume the above mentioned center position.

While I have shown a particular means consisting of the capacitance transformers described in the above mentioned patent to Eugene D. Eby for obtaining a suitable connection to the high tension lines 1 and 2 it will be understood that I do not wish to be limited thereto. since this is a preferred embodiment and other means may be employed P such for example as that disclosed in Patent No. 1,091,722 to V. A. Wolcott of March 31, 1914 consistingof a string of insulators, or

other high impedance conducting means,

connected between the high tension conductors and ground. Likewise, it will be understood that any suitable type of synchronoscope may be employed. v

While I have siown and described a particular embodiment of my invention it will, of course, be understood that I am not to be limited thereto since many modifications, both in the circuit arrangement and in the instrumentalities employed in carrying out my invention, may be made without depart iug from the spirit and scope of my invention as set forth in the accompanying claims. What I claim as new and desire to secure by Letters Patent of the 1. In a means for indicating synchronism betweenf voltages on a plurality of conductors, the combination with a synchronoscope, of capacitance transformers associated with each of said conductors and power amplifying means associated with each of said capacitance transformers, said amplifyin means being adapted to' supply to sai United States, is 2- chronoscope voltages bearing a substantially constant phase relation to the voltage on said transformers.

2. In a means for indicating synchronism between voltages on a plurality of conductors, the combination with a synchronoscope, of capacitance transformers associated with each of said conductors and power amplifying means for supplying alternating current energy from said capacitance transformers to said synchronosco e, the input and output voltages of sai ampli'f ng means being in substantiall the same phase relation with respect to t at of said conductors.

3. In a means for indicating synchronismbetween voltages on a plurality of conductors, the combination with a synchronoscope, of capacitance transformers associated with each of said conductors, each of said capacitance transformers comprising a pair ofconducting cylinders situated concentrically with respect to said conductors, the

'phase relation to that on said conductors.

4. In a means for indicating synchronism between voltages on a plurality of conductors, the combination witha synchronosco e, of conducting means located between eac of said conductors and ground and dielectrically se arated therefrom, means for rotectin said conducting means against outside disturbances, vacuum. tube amplifymg means adapted to supply voltage from each of said conducting means to said synchronoscope, the cathode circuits of said amplifying means being maintained at ground potential.

5. a means betweenvoltages on a plurality of conductors, the combination with a synchronoscope, of high impedance conducting means situated between each of said conductors and ground and hav1n voltages impressed thereon from said con uctors, means for protecting said conducting means from outside disturbances, and power amplifying means associated with each of said conducting means and adapted to supply voltage to said synchronoscope, each 0 said amplifying means havmg input circuits of sufiiciently hi h impedance substantiall to preclude the ow of currents therein an adapted to supply potential to said synchronosco e bearing a substantially constant phasere ation to that on said cond'uctors- In witness whereof, I have hereunto set my hand this 3rd da of June, 1927.

ELLS ORTH D. COOK.

for indicating synchronism 

